BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The invention relates to semi-trailers or tractor-trailers, and in particular to a device especially useful with the tractor for controlling and/or indicating the status of certain functions in the trailer. More particularly, the invention is directed to a portable control and monitoring device for the tractor which obviates the need for hardwiring a control and monitoring module in the tractor.

BACKGROUND ART The semi-trailer industry utilizes a standard 7-way connector cable for electrical communication between the tractor and the trailer of a semi- trailer. A separate 7-way receptacle typically is hardwired to each of the electrical systems of the tractor and the trailer. More specifically, a 7-pole socket is hardwired to the tractor electrical system, and a separate 7-pole socket is hardwired to the trailer electrical system. A coiled connector cable having a plug assembly at each of its ends is utilized to provide the electrical communication between the tractor and the trailer via the sockets.

A separate control/monitoring module typically then is hardwired into the electrical system of each of the tractor cab and the trailer, to enable monitoring of certain trailer accessories from the cab, such as anti-lock braking system (ABS) status, low or high reefer temperatures, axle overloading, bulkhead pressures, and the like. The monitoring typically is accomplished with indicator lights disposed in the tractor cab and electrically connected to the cab module. The cab module also can be

utilized to control, usually via switches located in the cab and electrically connected to the module, trailer devices such as auxiliary lift axles, air suspension system dump valves, alarms, lighting, refrigeration and heating, and the like. Such multiple control/monitoring functions can be achieved. over the standard and limited electrical system circuits of a semi-trailer, due to the utilization of existing multiplexing technology which enables communication of a plurality of messages or electrical signals across a single electrical circuit.

While this prior art arrangement of parts is effective in its intended use, it fails to compatibilize the use of tractors lacking hardwired multiplexer modules with multiplexer module equipped trailers, without hardwiring a multiplexer module to the tractor. Similarly, the known prior art also fails to provide for the use of trailers lacking hardwired multiplexer modules with multiplexer module equipped tractors. Obviously, the known prior art also requires hardwiring of a multiplexer module into both a tractor and a trailer if neither is equipped with a module. When a multiplexer module is added to a tractor, control switches and/or indicator lights must also be electrically connected to the module and mounted in the cab, usually on its dashboard.

The present invention solves the above-noted problems by use of a portable multiplexer device which includes control switches and/or indicator lights, and which can be plugged into any power point, such as a cigarette lighter, available in the non-multiplexer module equipped tractor and/or trailer to make the non-equipped vehicle immediately compatible with the equipped vehicle without requiring permanent electrical hardwiring, or to make two non-equipped vehicles instantly compatible.

SUMMARY OF INVENTION Objectives of the present invention include providing a portable vehicle control and monitoring device which can be used in a towing or power vehicle such as a tractor of a semi-trailer and/or in a towed vehicle such as a trailer of a semi-trailer, in order to make one or both of the

vehicles lacking a hardwired control and monitoring module compatible with the other vehicle.

Another objective of the present invention is to provide such a portable vehicle control and monitoring device which is relatively. economical to manufacture, and convenient, durable and reliable in use.

These objectives and advantages are obtained by the vehicle having an electrical system and means for generally non-permanently electrically connecting an electrical device to the electrical system, wherein the improvement comprises a portable multiplexing electrical device, the portable device being removably electrically connectable to the electrical system, so that at least one electrical signal is transmittable between the portable device and the electrical system.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiments of the invention, illustrative of the best mode in which applicants have contemplated applying the principles, is set forth in the following description and is shown in the drawings and is particularly and distinctly pointed out and set forth in the appended claims.

FIG. 1 is an elevational view of a prior art semi-trailer, with portions of its electrical system shown in phantom lines, showing control/monitoring modules hardwired into the tractor cab and the trailer and further showing the electrical cable connection between the tractor and the trailer; FIG. 1A is a plan view of a control/monitoring module of the type which is hardwired into a tractor or a trailer; FIG. 2 is a view similar to FIG. 1, with portions broken away, but showing the portable control/monitoring device of the present invention electrically connected to the tractor electrical system without hardwiring; FIG. 3 is a fragmentary perspective view of a plug and a receptacle of the industry standard 7-way connector for connecting the electrical systems of the tractor and the trailer; and

FIG. 4 is a plan view of the portable control/monitoring device of the present invention.

Similar numerals refer to similar parts throughout the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT So that the portable vehicle control and monitoring device of. the present invention and the environment in which it is useful both can be best understood, a prior art semi-trailer utilizing multiplexer technology, and specifically hardwired control/monitoring modules, will be described in detail hereinbelow.

A semi-trailer of the type which is well known in the transportation industry is indicated generally at 10 and is shown FIG. 1. Semi-trailer 10 inclues a towing power vehicle or a tractor 11 and a towed vehicle or a trailer 12.

On a typical semi-trailer, there are many functions of the trailer which are desirable to control and/or monitor from the tractor. Functions to be controlled include those achieved by auxiliary lift axles, air suspension system dump valves, security door alarms, lighting, refrigeration and heating, and the like. Functions to be monitored include anti-lock braking system status, low or high reefer temperatures, axle overloading, bulkhead pressures, and the like. To accomplis this control/monitoring function, multiplexer modules 13A, B (FIG. 1A) are hardwired to the tractor electrical system 14 and the trailer electrical system 15, respectively. The tractor multiplexer module then typically is in turn electrically connected to control switches and indicator lights (not shown) mounted on the dash of tractor 11.

Tractor and trailer electrical systems 14,15, respectively, typically communicate electrically via an industry standard and commonly available J560 7-way connector cable 16. As best shown in FIGS. 1 and 3, a 7-pole socket or receptacle 17 is mounted on each of the rear outside portion of tractor 11 and the front outside portion of trailer 12, with the respective

receptacles being electrically connected to the tractor electrical system 14 and the trailer electrical system 15.7-way connector cable 16 includes a cord 18 having a 7-pole plug 19 attached to each of its ends. Each of plugs 19 is removably engaged with a selected one of receptacles 17 to form an electrical connection between tractor and trailer electrical systems 14 and 15, respectively, as best shown in FIG. 1.

The above-described prior art arrangement of parts enables the multiplexer technology contained in modules 13 to accomplis the control/monitoring functions over existing industry electrical circuits of electrical systems 14,15, and connector cable 16, without requiring the use of separate additional electrical wiring systems or an altogether new increased capacity wiring system. The control/monitoring functions typically are performed/viewed, respectively, from tractor 11 by the operator of semi- trailer 10 using the switches/lights, respectively, electrically connected to module 13A, but can also be performed/viewed from trailer 12 using switches/lights electrically connected to module 13B, if desired. Modules 13 are available from Hendrickson Vehicle Control Systems of Canton, Ohio and are marketed under the CONTROL LINK trademark, or from Air Weigh Products of Eugene, Oregon under the WIRELINK trademark.

The present invention shown in FIG. 2 is identical to the arrangement shown in prior art FIG. 1, except that tractor multiplexer module 13A and associated switches/lights, which is hardwired into tractor electrical system 14, is replaced with a portable multiplexing control/monitoring device 25 (FIG. 4). Device 25 of the present invention preferably includes four switches 28 for control functions and four indicator lights 29 for monitoring functions. Portable control/monitoring device 25 of the present invention can be removably electrically connected to tractor electrical system 14 at any power point in the tractor, such as a cigarette lighter power point receptacle (not shown), via a usual cigarette lighter plug 26 attached to and electrically connected to device 25 via a coil cord 27.

Alternatively, plug 26 can be attached directly to device 25 without a coil

cord disposed therebetween. Still another contemplated embodiment would be to electrically connect device 25 to a binding post disposed in tractor 11 in a manner well-known in the semi-trailer art. If desired, module 13B also can be replaced with portable device 25 if a power point is utilized in trailer 12. Power points can even be provided on the outside of tractor 11 or trailer 12 for using device 25.

Thus, it can been seen that device 25 of the present invention can provide the desired control/monitoring functions on a tractor 11 and/or trailer 12 unequipped with a hardwired multiplexer module 13. Thus, portable device 25 simply can be plugged into the cigarette lighter or other power point of a tractor 11 lacking a multiplexer module 13A and the control/monitoring functions of the device become operational if trailer 12 is equipped with a module 13B. Conversely, portable device 25 of the present invention also enables a trailer 12 lacking a multiplexer module 13B to be used with a tractor having a module 13A hardwired into tractor electrical system 14. Of course, if neither tractor 11 or trailer 12 has a module 13 hardwired thereto, two portable devices 25 could be utilized, one each for the tractor and the trailer, to obtain the desired control/monitoring functions between the tractor and the trailer.

As set forth above, it is understood that portable control/monitoring device 25 can have a plug attached directly thereto, or be utilized with a coil cord 27 as shown in FIG. 4 to enable the operator of the semi-trailer to step out of the cab with the coil cord embodiment while holding the device 25, and visually observe whether the functions being controlled and monitored are occurring. The latter visual observation could also be accomplished by plugging either the coil cord or non-coil cord embodiments of device 25 directly into a power point located outside of tractor 11 or trailer 12. Moreover, it is understood that the present invention can be utilized with various types of vehicles wherein a towing vehicle and a towed vehicle are utilized other than semi-trailers. An example of another type of vehicle is a straight truck such as a dump truck.

In addition, the present invention could be used in a stand-alone vehicle such as a car or truck, to control/monitor functions of the vehicle from the interior of the vehicle. Also, the present invention contemplates use of device 25 with a plurality of towed vehicles or trailers, and further. contemplates the use of a plurality of devices 25 within tractor 11 and trailer 12 if additional functions are desired to be controlled/monitored. It is also understood that current multiplexing technology enables control/monitoring of up to 256 functions per electrical circuit, but the concept of the present invention could expand with expansion of multiplexing technology enabling greater than 256 functions per circuit.

Accordingly, the portable control and monitoring device of the present invention is simplified, provides an effective, safe, inexpensive, and efficient device which achieves all the enumerated objectives, provides for eliminating difficulties encountered with prior hardwired multiplexer modules, and solves problems and obtains new results in the art.

In the foregoing description, certain terms have been used for brevity, clearness and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed.

Moreover, the description and illustration of the invention is by way of example, and the scope of the invention is not limited to the exact details shown or described.

Having now described the features, discoveries and principals of the invention, the manner in which the improved portable control and monitoring device is constructed, arranged and used, the characteristics of the construction and arrangement, and the advantageous, new and useful results obtained; the new and useful structures, devices, elements, arrangements, parts and combinations are set forth in the appended claims.